Welcome to Medical News Today

Healthline Media, Inc. would like to process and share personal data (e.g., mobile ad id) and data about your use of our site (e.g., content interests) with our third party partners (see a current list) using cookies and similar automatic collection tools in order to a) personalize content and/or offers on our site or other sites, b) communicate with you upon request, and/or c) for additional reasons upon notice and, when applicable, with your consent.

Healthline Media, Inc. is based in and operates this site from the United States. Any data you provide will be primarily stored and processed in the United States, pursuant to the laws of the United States, which may provide lesser privacy protections than European Economic Area countries.

By clicking “accept” below, you acknowledge and grant your consent for these activities unless and until you withdraw your consent using our rights request form. Learn more in our Privacy Policy.

Please accept our privacy terms

We use cookies and similar technologies to improve your browsing experience, personalize content and offers, show targeted ads, analyze traffic, and better understand you. We may share your information with third-party partners for marketing purposes. To learn more and make choices about data use, visit our Advertising Policy and Privacy Policy. By clicking “Accept and Continue” below, (1) you consent to these activities unless and until you withdraw your consent using our rights request form, and (2) you consent to allow your data to be transferred, processed, and stored in the United States.

Get the MNT newsletter

Email an article

You have chosen to share the following article:

How elderberries can help you fight the flu

To proceed, simply complete the form below, and a link to the article will be sent by email on your behalf.Note: Please don't include any URLs in your comments, as they will be removed upon submission.

We do not store details you enter into this form. Please see our privacy policy for more information.

Vitamin D and bowel cancer

Recently, researchers from a host of organizations, including the American Cancer Society (ACS) in Atlanta, GA, the Harvard T.H. Chan School of Public Health in Boston, MA, and the United States National Cancer Institute in Rockville, MD, combined forces to investigate vitamin D's role in colorectal cancer risk.

Aside from skin cancers, colorectal cancer — which is also called bowel cancer — is the third most common cancer in the U.S. It is expected to claim more than 50,000 lives in 2018.

Understanding what factors play a role in its development is crucial. And, if vitamin D is involved, it might form the basis of a simple and cost-effective intervention.

Some previous studies have found a link between vitamin D deficiency and colorectal cancer, but others have not. This new, large-scale effort was designed to iron out the creases and present more concrete evidence.

Co-senior study author Stephanie Smith-Warner, Ph.D. — an epidemiologist at the Harvard T.H. Chan School of Public Health — says, "To address inconsistencies in prior studies on vitamin D and to investigate associations in population subgroups, we analyzed participant-level data, collected before colorectal cancer diagnosis, from 17 prospective cohorts and used standardized criteria across the studies."

In all, the team used data from studies conducted on three continents that included 5,700 cases of colorectal cancer and 7,100 controls.

Previously, researchers found it difficult to pool data from different studies because of the variety of ways that vitamin D was measured. These researchers calibrated the existing measurements so that a direct comparison could be made between multiple trials in a meaningful way.

Vitamin D's influence on cancer

The researchers compared each individual's vitamin D levels with the current National Academy of Medicine recommendations for bone health.

People who had vitamin D levels below the current guidelines had a 31 percent increased risk of colorectal cancer during the follow-up — an average of 5.5 years. Those with vitamin D above the recommended levels had a 22 percent reduction in risk. The link was stronger in women than in men.

These relationships remained significant even once the team had adjusted the data to account for other factors that are known to increase colorectal cancer risk.

But, it is worth noting that the reduced risk did not become more pronounced in the people with the highest levels of vitamin D in their system.

"This study adds new information that agencies can use when reviewing evidence for vitamin D guidance and suggests that the concentrations recommended for bone health may be lower than would be optimal for colorectal cancer prevention."

Marji L. McCullough

This study adds to the evidence that vitamin D offers protection against bowel cancer. Guidelines on vitamin D intake may need to be changed in light of these findings.

2019 Healthline Media UK Ltd. All rights reserved. MNT is the registered trade mark of Healthline Media. Any medical information published on this website is not intended as a substitute for informed medical advice and you should not take any action before consulting with a healthcare professional.